As an antenna for a point-to-point communication line, a parabolic antenna has been widely used. Particularly when a severe low side lobe characteristic is required, an offset parabolic antenna may be used.
In Patent Literature 1, an offset parabolic antenna is disclosed in which a worker can easily perform adjustment work of a polarization plane angle. The Patent Literature 1 discloses a method for offsetting a position of an antenna attachment pole with respect to a reflector lateral center, and mounting the offset parabolic antenna.
While realization of the low side lobe characteristic is an important object in the parabolic antenna, it also becomes an important object to have a strength maintaining structure in consideration of the wind pressure load resistance in design of the parabolic antenna. Particularly, when a technique for realizing the low side lobe characteristic is adopted in which an unnecessary radiation shielding plate called a shroud is provided, a wind pressure load tends to increase since a wind receiving area becomes large with respect to a crosswind.
It is necessary in the parabolic antenna to strengthen an antenna mounting mechanism for mounting the parabolic antenna to the antenna attachment pole in order to improve a strength characteristic of the wind pressure load resistance, which increases a degree of difficulty in antenna manufacturing, and becomes a factor for increasing a cost of manufacturing an antenna device.
As a method for attaching a parabolic antenna having a comparatively high strength wind pressure load resistance, there is included an attachment method disclosed in Patent Literature 2. In the attachment method, the parabolic antenna has a structure for covering an antenna attachment pole with a reflector mounting part from an upper part thereof, and thereby the strength of the wind pressure load resistance is improved.